Starter motor control system



July 10, 1951 D. DODGE STARTER MOTOR CONTROL SYSTEM Filed Oct. 19, 1949 TO vqcz/um I mmns l VlIIIIIlIIIIIIIII ll 1 STARTER l- RELA v STARTER STARTER BUTTON u '7'- IGNITION g SWITCH Patented July 10, 1951 UNITED STATES PATENT OFFICE 4 Claims.

This invention relates to a starter motor control system. More particularly, it deals with a circuit to control the energizing of an electric starter motor for an internal combustion engine having an electric ignition system, which prevents energizing said starter motor while the internal combustion engine is running.

Previously, such circuits have been controlled either by the vacuum intake of the engine or the electric generator current developed by the running of the engine, or both, but none of these circuits to prevent energizing of the starter motor during the running of the engine have been reliable under all conditions of operation of the engine, such as when the vacuum in the intake substantially disappears when the engine is quickly accelerated, or when the generator current drops, and/or when a short or a break occurs in the control circuit itself.

Accordingly, it is an obj ect of this invention to provide a simple, efficient, economic and completely effective control system for a starter motor for an internal combustion engine having an electric ignition system, such as employed in motor vehicles.

Another object of this invention is to provide such a control system which is reliable under all conditions of operation of the engine and which does not prevent energizing the starter motor to start the engine in the event of any failure in the control system itself.

In accordance with this invention, the electric starting motor system comprises two electric cirsuits, one for starting the motor which may be directly or indirectly connected, and the other for controlling or cutting off the first or starting motor circuit. The first circuit contains the conventional starter motor, current source such asa battery, and starter switch plus a normally closed cut-offswitch. The other and second circuit for controlling the firstand just mentioned starter motor circuit, contains the conventional ignition switch for the ignition system of the engine, plus a normally Open switch closed by the vacuum from the intake of the engine when th engine starts, and a self-holding electromagnetic means such as relay or solenoid, which when energized by the closing of the vacuum switch, opens the normally closed cut-off switch in the first starter motor circuit, whereby the starter motor control circuit, remains open until the other and second cut-off control circuit is broken by the opening of. the ignition switch. Thus, if the engine stalls, it cannotv be restarted until the ignition switch is, closed and opened again. However, if any.

failure occurs in the second cut-off control circuit, such as the burning out of the electromagnetic, means or any other break in this circuit, a spring connected to the cut-off switch will close it in the first and starter motor circuit so that the starter motor can be operated in the normal.

and usual way as if the cut-off system of the invention were not employed.

The above mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawing which is a schematic wiring diagram of the control circuits of the system of this invention.

Referring to the drawing, there is shown the conventional type of starter motor circuit for an automobile internal combustion engine comprising a current source or storage battery It and a starter motor I I connected through a heavy duty switch l2 by conductors I3 and Id. The switch [2 is closed only when the starter motor is to be energized and may be closed manually by a push button, or indirectly by a starter relay l5 as shown, which is energized by a starter motor control circuit comprising the actuating coil N5 of the relay l5, conductors I1 and I8, anda starter push button switch 20, which may be mounted on the dash board of the automobile. Also on or near the dash board may be mounted the ignition switch 25 which connects the battery I!) through conductors 26 and 21 to the ignition points of the engine. All of the above elements are common to the; electric starting and ignition systems of most automobiles.

The present invention consists of an additional and second control circuit, shown inside of thedotted rectangle 30, which comprises a cut-off switch inserted between the conductors l1 and; 18 of the starter motor circuit, a vacuum operatedswitch closed by the vacuum created in the intake manifold of the engine when th engine starts, and a self-holding electromagnetic means such as a solenoid to operate the cut-off switch 35 connected by a conductor 5']. This second control circuit is energized through the ignition switch 25 and connecting conductor 52. Each of the switches I2, 20 and 4B are shown to be normally maintained open, insured by the action of compression springs l9, 2| and 4|, respectively, and cut-01f switch 35 is normally main.- tained closed, insured by the action of compression spring 36.

The vacuum operated switch 40 may comprise a movable contact 42 connected to a movable cork covered cap 43 which seals the end 44 of the tube 45, connected to the intake manifold of the engine, when a vacuum is created in the intake to produce a suction at 44. This movement of the cap 43 and its contact 42 closes the switch 40.

In order to start the internal combustion engine according to the system of this invention, first the electric ignition switch 25 is closed. At this time the starter switch l2 and starter control push-button switch 20 and vacuum operated switch Ml are open, and since the second control circuit 30 of this invention has not as yet been energized, the cut-off switch 35 is closed, all as shown in the drawing.

Next the manual starter button is pushed to close the switch 25. This energizes the starter relay l5 by a circuit from ground 22, through the contacts of switch 20, conductor I8, switch 35, conductor [7, coil [5, conductor 13, battery l and back to ground at 9. The energization of coil l6 operates the relay 15 to close the heavy duty switch l2 which closes the circuit from ground 9, through battery It, conductor l3, switch [2, conductor l4, starter motor H and back to ground at 8, so that the starter motor is now energized and cranks the engine to start it.

When the engine starts, a vacuum is created in the intake manifold to cause a sufficient suction at 45 to close the cap 13 and switch Ml. This closes the second control circuit 30 from ground 45 through switch 45, conductor solenoid 55, conductor 52, ignition switch 25, conductor 26, battery it and back to ground at 9. This second cut-off control circuit energizes the electromagnetic means 59 to open the cut-off switch 35 and close its self-holding contacts 53 and 54, which may be with the electrically isolated conducting bridge 55 of the switch 35, or by a separate conducting bridge means. The opening of the switch 35 breaks the startercontrol circuit which in turn breaks the heavy duty starter motor circuit by opening heavy duty switch [2, and stops the starter motor whether switch 20 is still held closed or not, as well as preventing the switch 26 from later closing the starter motor circuit as long as the engine ignition circuit is energized and the switch 35 is held open by the energized electromagnetic means 55. The holding circuit for the electromagnetic means is through nowclosed contacts 55 and 54 to ground 55, in parallel with or short circuiting the circuit to ground 46 through the vacuum operated switch 45. Therefore, regardless whether or not the vacuum operated switch may open due to rapid acceleration of the engine, such opening will not permit the closing of the starter motor circuit by the closing of cut-out switch 35. 1 In order to stop the engine, the ignition switch 25 must be opened, which breaks the second control circuit 35 and permits the conducting bridge 55 to again close the switch 35 due to the action of the spring 36. The stopping of the engine then permits the vacuum operated switch 40 to open, insured by the action of the spring 4|, and the starter button switch 20 is again connected in the starter motor contro1 circuit so that the engine may again be started as described above. If the engine stalls, dies, or stops while the ignition is still on, the circuit 30 remains energized and the switch 35 remains open so that the ignition must be turned off, or the ignition switch 25 opened, and then turned on or closed again, before the engine can be started in accordance 4 with the operation of the circuits described above. Such an additional cutting of the ignition each time before the engine can be started, insures that the starter motor can never be energized during the operation of the motor regardless of how weak the vacuum on the intake manifold becomes.

Furthermore, if any part of the circuit 3!! fails or burns out, the engine can always be started in the regular manner because the spring 55, then closes the switch 35 so that the known conventional elements of the starter motor circuit may be used in the conventional way, the only disadvantage being that the cut-off switch no longer insures the cut-off of the starter motor while the engine is running.

, Although the above embodiment has been described for an indirect type of starter motor control circuit containing a starter motor relay [5, the same principle of this invention may be applied to such a circuit directly in which the switch I2 is replaced by the manual push button switch 20 and the normally closed cut-off switch 35. The reason that the starter motor energy supply circuit from battery Ill through switch I2 to the starter motor I l is preferably made separate from the push button circuit, is because that the amount of current required for the motor 2'! is so great that it requires very heavy conductors, and switch contacts. Accordingly, the fewer number of such heavy switches and the less amount of such heavy conductors employed, the more economical and simpler the installation becomes.

Another advantage of the present invention is that it can be installed easily into any existing starter motor control system without changingany of the existing conductors. All that need to be inserted are the contacts of normally closed cut-01f switch 35 in the starter motor control circuit, and the only other additional equipment which needs to be installed is the vacuum operated switch 40 and the electromagnetic means 50, which are connected to terminals or contacts existing already in the control system.

While there is described above the principles of this invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of this invention.

What is claimed is:

- 1. An electric starter motor circuit for an engine having an electric ignition system which en-' gine produces a vacuum, comprising a starter motor circuit containing a starter motor, a normally open starter switch and a normally closed cut-off switch; and a control circuit for said starter motor circuit containing the ignition switch of said engine, a vacuum closed switch, a solenoid to open said normally closed switch to break said starter motor circuit, and means to maintain said solenoid energized as long as said i nition switch is closed.

2. The system of claim 1 wherein said means to maintain said solenoid energized comprises a pair of self-holding contacts in the energizing circuit of said electromagnetic means.

3. The system of claim 2 wherein said pair of self-holding contacts are in electric parallel to the contacts of said vacuum operated switch.

4. In a starter motor circuit for an internal combustion engine having an electric starter motor, anintake manifold, a starter switch, an electric ignition switch-and an electric current source, the improvement comprising a normally DONN L. DODGE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Varley June 22, 1920 Williams et a1 Nov. 6, 1926 Guettner, Jr Apr. 8, 1933 Geraghty Mar. 27, 1934 Maurer Dec. 10, 1935 Liverance, Jr June 22, 1938 McCracken Feb. 14, 1950 

